Plexiglass Glue. PLZ Help!

T

Taradino

Limp Gawd
Joined
Nov 11, 2005
Messages
147
I want everybody's input.

I have created my custom made water tank for my pc, I have put Clear Silicon on the edges where it is rough, it sticks.

I found i have a suddle leak and so I want to glue all the edges but this IS NOT rough, this is the sides of the plexiglass so its all smooth.

I have tried to glue with the following:
Silicon (clear, Marine, regular white shit)
Epoxy (Clear, Marine, Regular, car epoxy)
Construction Athesoph (spelling I know, but my gf distracted me.... ;)
hmm, what else.
Zap-It
Crazy Glue
Instant bond
Bondo
Methlyene Chloride works but its a solvent

NOTHING sticks!

Has anybody used this?

IPS Weld ON #4 (number for NOT number 3)
http://www.tapplastics.com/shop/product.php?pid=131&
water tight super thin and dries crystal clear its best to apply this thinly with a needle bottle applicator

What I need is something that would stick to smooth plexiglass...

Any ideas?
 
The issue with the #3 is it is a liquid like water, where by using the capilary action, it will get into the cracks of the plexiglass.

My issue is, the plexiglass is already glue together, I need something that will seal the edges. Where the 2 edges make an "L" and I want to seal where it meets that will stick to the smooth plexiglass.
 
I need a glue or something that would go on like Epoxy and just would NEVER come off.
 
the weld on stuff does just that, it welds the 2 pieces together. if you are looking for something like epoxy that has substance to it you need a higher number weldon. there is a 2 piece weld on product, 16 i think? not totally sure. but the stuff when combined will weld 2 pieces together and form acrylic itself in any spaces much like epoxy resin.

-el
 
number 16 comes in a tube that has a thicker consistency that is easy to work with. to use number three or four you'll need a squeeze bottle with a flexible syringe type of needle at the end.
 
yeah i got the numbers wrong, i was thinking 16 because thats the stuff i like to use, it has a thin syrup consistancy i like, but its actually weldon #10 or weldon #40 that you want. they are 2 part structual acrylic glue.
http://www.rplastics.com/plac.html
you can see both of them there, along with a bunch of other glues.

I have never used either product and i dont know the difference between 10 and 40 though.

-El
 
hot glue won't stick worth ...... (ends with it)

I found a solution I will get the name soon but it works REALLY well.
 
Araldite, it has 2 tubes, one is the glue and the other is the bonder and it sticks to itself, so u can put it on anything and it will work.

Heck i even put it on the inside of a freezer when i was defrosting it, i chipped the elements and gas started to leak out of it, ok i know I shouldnt of been using a chisel to scrape the ice out to make defrosting faster, but that thing held for over a year before I got another freezer.

If I recall, it is an epoxy, so it should fit your needs perfectly.
 
I do alot of acrylic work because of my other hobby... my reef aquariums, and I go through alot of plexi sheets/pipes/etc.

You want to use weld-on (IPS), no doubt about it. Silicone and other glues dont bond, and will eventually seperate. So all that silicone is an accident waiting to happen as after some time, it will just let go. You can use #3 or #4... they are really the same (#3 isnt any more for Lexan than #4 is), just that #3 dries alot faster. If you can work fast, #3 is all you need. If you think you need some time, and can tape together/brace the pieces, use #4. #16 is a thicker cement for filling in corners, and for bonding PVC to acrylic (it works on PVC rather well). You CAN use it, but it isnt needed. The other numbers arent anything you need to bother with for acrylic...just 3,4, and 16.

The other thing of critical concern here that often gets overlooked is the TYPE of plexiglass being used. The stuff you get at Lowe's and HD, and for that matter, just about everywhere else, isnt suitable for underwater use. It will be fine for windows, but these plexis are extruded, and extruded can absorb up to 60% of its weight in water!!! When it does, it expends, and your bonds will eventually 'craze'...and split. Its just a matter of time... they will split.

The proper type of acryic to use for any water application is cast acrylic. It costs about 2x as much, but its also much stronger... so a thinner piece can often do. Cast bonds better, is more scratch resistant, and will not absorb as much water, so it is the acrylic you want to use.

A acrylic-worker's secret: If you dont have weldon or dont want to pay for it... the primary ingredient is Methyl Ethyl Ketone (<<<did I spell that right?), a chemical that is easily found at your local HD paint department. If you blend a 1:1 by volume mix of this to acrylic shavings (slice up, shave up, etc, blend and let dissolve) you can have a very good bonding glue. If you want thicker, just add more acrylic shavings...thinner, use less...just beware that less acrylic can result in crazing and drying too fast for a good bond, so dont get carried away.
 
My brother (a small engine mechanic) gave me industrial "Plastic Quick Fix" by Kent Automotive. The stuff is like a two part epoxy (smells like it).
It is the same (well basically) what the automotive industry uses to seal up car parts (from everything).

Works AMAZINGLY well with plexiglass (and also sticking fingers together).
 
I've always used the weld on and after letting that cure, not sure if it needs it, but I let it sit for a week. then I seal both sides with a chemical resistent silicon. I nice thin bead and smooth it down with your finger and water. I do that to both the inside and outside. I let that sit for another week. I know it seems like a long time, but 2 weeks is worth it when you don't have any leaks. I've used reseviors like this sitting at the top of my cases where any drop of water could fry any number of parts, so i need that peace of mind.
 
bigbadgreen said:
I've always used the weld on and after letting that cure, not sure if it needs it, but I let it sit for a week. then I seal both sides with a chemical resistent silicon. I nice thin bead and smooth it down with your finger and water. I do that to both the inside and outside. I let that sit for another week. I know it seems like a long time, but 2 weeks is worth it when you don't have any leaks. I've used reseviors like this sitting at the top of my cases where any drop of water could fry any number of parts, so i need that peace of mind.
Click to expand...

I hate to say it, because it seems as though you put alot of effort into it, but beyond the weld-on, everything you do after that (letting it sit for a week, seal with silicone, etc) is completely useless. The silicone wont hold for more than a year before its seperated from the plastic (silicone only bonds to silica, glass, porcelain, quartz, etc), and weld-on only needs a few hours to dry. Weld-on works by actually dissolving the two pieces of acrylic, and then drying leaving a chemical weld that, if done right (and right just means little bubbles, etc), is just as strong & sealed as anywhere else on a solid sheet of plexiglass.

I dont want to be mean, I hope that this saves you, and others reading, some time in the future. If anything, I would worry about the silicone coming off over time and getting stuck somewhere it shouldnt. how do you coat the entire inside and outside anyways? Silicone sealant spray?

As for the weld-on, #3 is ready to go after about 15 minutes really... #4 I would give an hour, and #16 perhaps a couple hours for it to complete hardening and drying since it does retain its solvent better. But #3, I have used to bond just seconds before going underwater, and not only is it safe, but completely solid forever (as long as you use cast acrylic, not extruded of course).
 
I wasn't taking it as mean at all, we all have our ways of doing things. First off I don't seal the entire outside of the resevior. I seal both the inside and outside of the joints only. I also realize how weld-on works. But for security reasons I use a silicon sealant on the joints as well. The product I use is Devcon Silite RTV. It's a high temp, chemical resistent sealant adhesive. It is used for water proofing electrical components, caulking plumbing fixtures, sealing glass, and for making gaskets.

I have one resevior that has been in use continuously for just over 3 years that still looks like the day I sealed it. the problem with silicon seals is that people rely only on the silicon as the adhesive, they don't let it cure long enough, or people have a hard time choosing the right application.

This particular silicon is very resistent to glycols or antifreeze. I've never been worried about this breaking down. It's pretty much the same substance they use for making gaskets for high performance engines. If it doesn't break down at temps in the 150-300F range of car cooling systems I doubt my watercooling setup is going to push it.

I'm also not trying to be mean here, but silicon adhesives and sealants do bond to acrylic. If not why would dow make a product that specializes in sealing acrylic aquariums. It might not be the method you choose to use, and I certainly wouldn't use silicon by itself, but there are tons of sources out there by doing just a basic google search that back up using silicon as a sealant for acrylic aquariums. Here is a link to a professional aquarium builder website that states that they use an epoxy and then seal it off with a silicone sealer. http://www.aquariumpros.com/articles/series1turnkey.shtml
a quote from the site
"The FRP material forms a 3" retention lip in front of the front viewing panel and the acrylic panel was sealed in place with a special gel epoxy that remains flexible when dry and was then reinforced internally with silicone sealant"
this was a tank for a public site with 2 4ft black tipped reef sharks. I think if it's good enough for them it's good enough for me.
 
So with my tank that I created and I ran silicon glue on teh inside then put it all together. I ended up sealing it with the "plastic quick fix" stuff. my question is, would the silicon come apart within the tank?
I am concerned that the silicon would distindegrate and kill the pump.

The thing is, would my coolant really cause the silion to come off the plexiglass, the pump isn't strong enough to blast it off.

Thoughts?
 
bigbadgreen said:
I'm also not trying to be mean here, but silicon adhesives and sealants do bond to acrylic. If not why would dow make a product that specializes in sealing acrylic aquariums. It might not be the method you choose to use, and I certainly wouldn't use silicon by itself, but there are tons of sources out there by doing just a basic google search that back up using silicon as a sealant for acrylic aquariums. Here is a link to a professional aquarium builder website that states that they use an epoxy and then seal it off with a silicone sealer. http://www.aquariumpros.com/articles/series1turnkey.shtml
a quote from the site
"The FRP material forms a 3" retention lip in front of the front viewing panel and the acrylic panel was sealed in place with a special gel epoxy that remains flexible when dry and was then reinforced internally with silicone sealant"
this was a tank for a public site with 2 4ft black tipped reef sharks. I think if it's good enough for them it's good enough for me.
Click to expand...

You have misread the application of the silicone in this case. The reason silicone was used is because the tank's sides and bottom are made from FRP... fiberglass! So using Weldon would have been impossible. With acrylic to acrylic bonds, this compound would be useless. Unless the silicone is one of the special acrylic bonding types that is made, it will lose its stick and seperate from the acrylic all together. And the problem with the special acrylic bonding silicones is that most of them arent waterproof, or what you would consider 'food-safe', so they will give off chemicals over time or fail. In the case of the above Aquarium, the front panel was bonded in place with the special gel epoxy, but that gel epoxy is not waterproof, so it needed to be sealed, and luckily, silicone will bond to some other rubbers... so it was used as a covering. The silicone was not used as a 'bonding agent' with any acrylics, just a sealer. If you do some searching at websites like 'Reef Central', or even ask in their DIY section (where several acrylic fabricators and myself hang out as well), you will get informed on the subject. And these are guys who bond together alot of acrylic. Here's a project I did about a year ago... nothing but weldon... and its under 5' of water pressure 24/7...http://www.nano-reef.com/forums/index.php?showtopic=66406&hl=got+kalk\?

Every Acrylic Aquarium MFG I know of only uses Weld-On #4 to bond everything. Its all you really need. It is a chemical bond and water tight under pressure even. Adding silicone for a 'better seal' to a weld-on bond is a bit like welding together the frame of a car with metal, and then adding plumbers putty to the welds with the claim that you are 'sealing' it. It just doesnt do anything. No acrylic tank mfg uses silicone, just weldon. I can give you email addy's to a few of the builders themselves... it just doesnt work. For reef aquariums, sumps are used (a tank below the main tank where all the equipment is stored, the main display's water overflows into this sump, where a pump then pumps it back up to the main display). In these sumps, walls are made as baffles to direct the water and maintain water levels and overflows in the sumps. Glass aquariums are often used because they are cheaper...but plastic baffles are used as the dividers because they are easier to cut to fit (drill holes, etc). These baffles have to be done a certain way because the silicone will bond to the glass, but not to the acrylic. I have a wall in one of my sumps that is failing as we speak... so I know first hand how long silicone holds to acrylic. About 6 months to a year if its reinforced (clamped on the outside, etc), but less than a couple months if its used as a structural component.

There are some other products, like Goop. In my last talk with the makers of Goop, they claimed they were coming out with an Aquarium Goop... for among other things, bonding acrylic to glass which is impossible with silicone. The only thing silicone will bond to is other silica based substances (its in the name!!). It will stick to many things for a while.... but its not a bond. Glass, porcelain, some ceramics, etc... thats all. Besides that, weldon is just easier to work with too. As of yet, this Aquarium Goop was supposed to be out over a year ago, and is still vapor...

MoDsOuRcEdOtNeT, watch out with mixing acetone and plexi... I cant remember off the top of my head, but there is a reason why this is a big no-no (a bad chemical is released?). Like I said a little bit further up the page, use MEK if you want to mix your own Weld-on... much better weld as well (its the real deal). I have tried it with acetone in a pinch... but all I got was a surface bond that didnt hold under stress.
 
ok I'll take back the way I used bond. Not the right choice of words. However the application in that aquarium is pretty much the same thing I'm doing, just sealing. I understand that weld-on is watertight. I use the silicon as an added safety issue, just in case. The issue I had with the weld on initially is that there really is no way to test it to make sure you got every bubble out. I learned the hard way, and it was a mis-application by me, that water will find any gap, no matter how small. there is nothing quite like one small drop of water from an undetected leak that fries a new video card. I had leak tested for 48 hours with no leaks, and within a week I had a dead video card and an obvious culript. There was a spot of dried water on the card and a drop of coolant waiting to drop from the resevior.

Since that mishap I chose to use silicon as a security measure to make sure everything is sealed. While it's not needed, it's peace of mind for me. With the product I have used it has never shown signs of letting go or breaking down. I was worried about this at first. I have watched it an haven't seen anything over the past years.

So I guess we can agree to disagree. We both have our reasons and they both work for us.
 
have you ever used weldon #16? I think that this might be exactly what you are looking for..
 
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